The present invention relates to riser card assemblies for electronic devices, such as computers, and methods for their installation.
Conventional computers typically include a chassis that encloses circuit components, such as processors, memory chips, peripheral interface devices and other circuit elements. The core circuit components, such as the processor and the memory chips, are often mounted on a single printed circuit board, such as a motherboard. It is often desirable to provide the computer with expansion ports or slots for attaching additional printed circuit cards (xe2x80x9cexpansion cardsxe2x80x9d) having additional circuit elements. In this manner, a user or manufacturer can add additional capabilities and/or functions to the computer without significantly altering the existing computer structure. In one conventional arrangement, the expansion slots are provided on the motherboard. One drawback with this approach is that the expansion slots take up valuable space on the motherboard. One approach to addressing this drawback is to attach an intermediate riser card to a single slot of the motherboard and attach a plurality of expansion cards to the riser card. Accordingly, a plurality of expansion cards can be coupled to the motherboard via the riser card in an arrangement that occupies only a single slot on the motherboard.
Conventional computer chassis and motherboards come in a variety of shapes and sizes. For example, some xe2x80x9cfull-formxe2x80x9d conventional desktop computer chassis and tower chassis are dimensioned such that a single riser card, attached to the motherboard, can have six or seven expansion slots to accommodate expansion cards. A new type of xe2x80x9clow-profilexe2x80x9d chassis takes up less space than the conventional full-form chassis, but the low-profile has a limited height that cannot accommodate a riser card having six or more expansion slots. For example, in one low-profile configuration with an NLX motherboard that slides into the chassis, a riser card is attached directly to a low-profile chassis and the motherboard is coupled to one slot of the riser card. The low-profile riser card can include up to three additional expansion slots that each accommodate one expansion card. One drawback with this arrangement is that a different riser card may be required for low-profile and fill-form chassis, and still a different riser card may be required for ATX or NLX motherboards. Accordingly, computer manufacturers and suppliers may be required to provide and maintain an inventory of several types of riser cards, which can be expensive and inefficient.
The present invention is directed to riser cards for expanding the circuitry of a device such as a computer. In one aspect of the invention, the riser card can include a generally flat support member having a first connector for coupling to a circuit board (such as a motherboard) of a computer, a second connector for coupling to another riser card, a plurality of expansion ports for coupling to expansion devices, and coupling circuitry coupled to the first connector and the expansion ports. In a further aspect of the invention, like riser cards can be stacked one upon the other to increase the number of expansion ports coupled to the circuit board. Alternatively, the stacked riser cards can be different. For example, the lower riser card can include a connector for coupling to the circuit board and can include pass-through circuitry for coupling to the upper riser card. The upper riser card can include a connector for connecting to the lower riser card and need not include pass-through circuitry.
The riser card connectors can include one or more of several different types. For example, where the circuit board is a motherboard, the riser card can include a connector that is removably received by a corresponding connector of a motherboard. In one embodiment, the motherboard can be attached to a computer chassis and the riser card can be removably coupled to the motherboard. In another embodiment, the riser card can be attached to the chassis and the motherboard can be removably coupled to the riser card. The connectors can include edge connectors that face toward or perpendicular to the motherboard or alternatively, the connectors can be coupled to a ribbon cable extending between the riser cards.
The present invention is also directed to methods for expanding the circuitry of a circuit board by coupling one or more riser cards to the circuit board. In one aspect of the invention, the method can include removably coupling a first riser card to a connector of the circuit board, removably coupling a second riser card to the first riser card, and removably connecting at least one selected circuit device to one of the first and second riser cards. The method can further include passing electrical signals directly from the second riser card to the circuit board via the first riser card.
In another aspect of the invention, the same type of riser card can be used for several different types of computers. For example, the method can include coupling a first riser card to a site of a first circuit board of a first type of computer where the site is configured to accommodate at most a single riser card. The method can further include coupling a second riser card of the same type as the first riser card to a site of a second circuit board of a second type of computer. The method can still further include coupling, to the second riser card a third riser card such that each of thee riser cards has an expansion port accessible for connecting to a selected device.